Container positioning apparatus

ABSTRACT

A self-aligning multiple platform structure for handling large, heavily loaded containers to rapidly bring a container into approximate registry with the platform for a variety of purposes including pumping a fluid out of the container. Such approximate alignment is obtained by a combination of apparatus features including complementary locating members disposed on the bottom of the container and on the top platform which is easily movable horizontally along tracks fixed to the top of an intermediate platform which is easily movable in a crosswise direction along fixed parallel tracks on the base. Where more precise registry is required as in inserting a large follower plate into the open end of a container, slanted guides are affixed to the top rim of the container, preferably by means of detachable mountings, so that the vertically descending follower plate pushes against one or two slanted guides and thereby moves the container and top platform into precise registration with the follower plate.

i United States Patent [191 Elsworth 1 CONTAINER POSITIONING APPARATUS [75] Inventor: Robert M. Elsworth, Loudonville,

[73] Assignee: General Electric Company,

Waterford, NY.

22 Filed: Feb. 7, 1974 21 Appl. No.: 440,441

[52] US. Cl. 141/283; 141/370 [51] Int. Cl. B67C 3/34 [58] Field of Search 137/376; 141/65, 231-233, 141/235, 250, 270, 283, 284, 311, 312, 369,

[56] References Cited UNITED STATES PATENTS 3,810,500 5/1974 Brun et a1. 141/231 Primary ExaminerRichard E. Aegerter Assistant ExaminerFrederick R. Schmidt Attorney, Agent, or F irm-J0hn L. Young; E. Philip Koltos; Edward A. l-ledman Nov. 4, 1975 [57] ABSTRACT A self-aligning multiple platform structure for handling large, heavily loaded containers to rapidly bring a container into approximate registry with the platform for a variety of purposes including pumping a fluid out of the container. Such approximate alignment is obtained by a combination of apparatus features including complementary locating members disposed on the bottom of the container and on the top platform which is easily movable horizontally along tracks fixed to the top of an intermediate platform which is easily movable in a crosswise direction along fixed parallel tracks on the base. Where more precise registry is required as in inserting a large follower plate into the open end of a container, slanted guides are affixed to the top rim of the container, preferably by means of detachable mountings, so that the vertically descending follower plate pushes against one or two slanted guides and thereby moves the container and top platform into precise registration with the follower plate.

12 Claims, 2 Drawing Figures "ml "l CONTAINER POSITIONING APPARATUS This invention is concerned with the apparatus for the improved handling of heavy containers and like equipment which includes movable multiple platforms structures equipped with a self-aligning means for providing approximate registration of the platform with the container; and one embodiment incorporates an-.

other self-aligning means for moving the supported container equipment laterally into exact registration or alignment with additional equipment.

BACKGROUND OF THE INVENTION So-called X-Y tables are known in the art for supporting objects so that the position of the object may be adjusted by movement for a relatively short distance in any horizontal direction. Typically, these devices consist of some type of guide means located between a supporting base and a middle platform so that the platform can be moved back and forth relative to the base and of another guide means oriented differently between the middle platform and a top platform to render the top platform movable in a crosswise direction (i.e., 90 relative to the first mentioned direction) with respect to both the middle platform and the base. Both of these movements are straight line motions, and together they permit two dimensional movement in any direction in a single plane for distances that are restricted by the length of the various apparatus elements and usually by the need for maintaining the structure in balance. Unfortunately, it appears that these structures are available commercially as units capable of supporting a maximum load of only a few hundred pounds and they usually have a relatively small table.

There is a need for improved movable platform apparatus having self-aligning characteristics for shifting automatically and rapidly to accommodate a container or other object that may often be deposited somewhat off center as can easily happen when employing portable loading equipment, such as a fork lift truck in repeated operations. This need is intensified in the case of handling large containers or other bulky equipment, especially when the table or platform must withstand loads of thousands of pounds. Moreover, the problem is even more difficult when the top of such a table must be capable of shifting easily under the influence of a moderate horizontal thrust even when supporting a large and heavy container, as for example, to provide a precise registration of the container with another piece of equipment that is approaching for engagement with the container.

In handling the large and heavily loaded container and associated pumping equipment, which are described hereinafter, earlier efforts to move the container after it had been deposited on the floor beneath the pumps frequently involved five or six men using crowbars to shift the container by a laborious wedging 2 ratus; and then to pump fluid or semisolid materials faster and with greater ease using less labor and with fewer repairs and shut downs for that purpose.

SUMMARY OF THE INVENTION This invention relates to a self-aligning platform structure which comprises a plurality of substantially horizontal parallel rails affixed to the upper surface of a base member, an intermediate platform having bearing means therebeneath coacting with said base rails for supporting said intermediate platform for rectilinear movement along said base rails, a plurality of substantially horizontal parallel rails affixed to the top of said intermediate platform and longitudinally oriented substantially perpendicularly to the length of said base rails, a top platform for supporting a container and having bearing means therebeneath coacting with the platform rails for supporting said top platform for rectilinear movement along said rails, whereby said top platform is supported for easy movement in any horizontal direction relative to said base rails, at least one locating device on the upper surface of said top platform for engaging at least one complementary locating element on the bottom surface of a container as said container approaches said platform, at least oneof the locating means projecting from the associated said surface, and at least one of said locating means having a sloping surface capable of exerting any necessary camming action during the engagement of said locating means to provide any necessary horizontal movement of said top platform for locating said container in predetermined registry on said top platform.

Other aspects of the invention include one or more of such features as having at least part of the sloping surface of said locating means inclined at more than 30 relative to the horizontal,- preferably in the form of a hemispherical boss and desirably a plurality thereof for engaging a locating element projecting from the bottom of the container; and employing recirculating linear roller bearings, which preferably include sets of oppositely inclined bearingsfor engaging the sides of rails of circular cross section to preclude derailment.

Another modification of the invention includes a container supported on said top platform for engagement with additional equipment and guide means on the container for providing any necessary horizontal shifting of the container for registry with the other equipment, which guide means preferably has an inclined surface to provide a camming action. for precise registry, and the guide means may be provided with clamps for quick removal and attachment to the container. In one preferred embodiment, said additional action into their estimate of exact alignment with the r descending follower plate of the pump assembly. This aligning procedure was not satisfactory, because it was slow and also too costly in both manpower and the equipment incorporates a follower plate capable of vertical motion only in maintaining sealing contact with the contents of the container.

DESCRIPTION OF TI-IE DRAWINGS DESCRIPTION OF SPECIFIC EMBODIMENTS For a better understanding of the structure and-operation of the apparatus of the present invention, as well asits objects and aelVzliitagesreference should be had to the accompanying drawings and particularly to FIG. 1.

FIG. 1 illustrates the operation which will be described hereinafter of one of the self-aligning aspects of the invention; and it will be noted that the cylindrical tank is well centered on a self-aligning platform structure which is generally designated by the reference numeral 1 1 and that both of these pieces of equipment are out of registry with the circular follower plate 12 which is above the open top of the tank 10.

In order to provide for easy movement of the container 10 for a limited distance in any horizontal direction, the platform composite 11 is made up of a sizable number of apparatus elements which are enclosed within the cylindrical skirt 13 for protection against dust, spilled materials, etc. Only this skirt is shown in a diametrical cross section in FIG. 1 in order that the underlying mechanical elements may be seen.

Two or more stationary and parallel rails 14 of circular cross section are rigidly attached to the base plate 15 by bolts, welding or other suitable means. Base plate 15 is part of the strong and rigid frame 16 which is described hereinafter. Base rails 14 are aligned in parallel and horizontally in order that they may serve as tracks for all of the platform structures thereabove, and they are desirably made of hardened steel to substantially reduce the friction in comparison with that of conventional flat-surfaced tracks when operating under heavy loads. Such rod-like tracks 14 can be produced economically and with great precision by centerless grinding. The length of the tracks is a matter of choice, and they may well be kept short enough to remain within the protective cover of skirt 13 during use.

An intermediate platform 17 in the form of a strong plate of steel or other suitable material is horizontally disposed and mounted for rectilinear movement in one dimension only, that is back and forth horizontally in alignment with the lengths of rail 14. When the platform equipment is provided with skirt 13, the dimensions of plate 17 are kept small enough to allow for sufficient freedom of movement within the confines of the skirt. The distance of such travel or free movement of plate 17 is dependent upon a number of factors including the accuracy with which container 10 is deposited upon the platform structure 11 and the amount of travel subsequently required for aligning the container with other devices or equipment as described hereinafter. Plate 17 may be of octagonal, rectangular, circular or of other convenient shape. Affixed to the lower face of plate 17 by any suitable means (not shown) are a plurality of bearings 18 and 19, and two or more parallel rails 20 are also rigidly attached to the horizontal upper face of that intermediate platform.

The bearings ride on-the base rails 14 to provide for the movement of plate 17 and the equipment supported thereby along the base rails 14, preferably with as little friction as possible so that only a small force is required to move plate 17 even when it is loaded heavily. While the bearings may be of any appropriate type including simple pads or slides, it is usually preferable to employ bearing means equipped with balls or rollers for the desired low frictional resistance. For operations involving heavy loads on the platform structure 11, recirculating linear roller bearings of the types illustrated in a general fashion in FIG. 1 are particularly preferred, such as the Roundway bearings manufactured by Thomson Industries, Inc., Manhasset, N .Y., especially when employing tracks or rails 14 and 20 of circular cross section. Bearings of that type are known to exhibit very low friction in operating on round tracks, and the spaced rollers therein do not tend to rub or skew. Also the V-type of bearing 19 performs additional functions, as it both maintains correct alignment of the entire carriage of intermediate platform 17 with the rails 14 and also precludes derailment of that carriage from the tracks by reason of having two sets of the recirculating rollers 21 and 22 disposed at equal and opposite inclinations of about 45 to the horizontal and both in contact with the same section of round rail 14. For maintaining the alignment of bearings and rails, it is desirable to employ at least two of these twin bearings 19 and both may be running on a single rail 14, while two simpler single bearing sets 18 are used on the other rail; alternatively, one bearing unit of each type may be used on each of the rails. It is also contemplated that all the bearings may be a simpler type, as exemplified by bearings 18, and used in conjunction with other devices for maintaining alignment and preventing derailment of the platform carriages.

The composite platform structure 11 is also provided with another platform, a top platform 23, on which the tank 10 rests and from which the optional protective skirt l3 hangs. Like the metal platform 17, the top platform is a strong, flat, horizontal plate of circular or other suitable shape. Also, affixed to its lower face are the recirculating roller bearings 24 and 25 of the same type as bearings 18 and 19, respectively. Bearings 24 and 25 ride on the intermediate platform rails 20 which are parallel to one another and oriented at right angles to the base rails. Thus the upper platfonn 23 is movable back and forth in a transverse or crosswise direction relative to the line of travel of intermediate platform 17. Since platform 23 is carried by the middle platform 17 in its movement, the top platform is consequently movable in any direction horizontally within the limit of the rails 14 and 20. When the instant apparatus is equipped with the optional skirt 13 attached to the edge of platform 23, a top platform is employed which is substantially larger in diameter or breadth and the maximum measurement of platform 17 (e.g., about 2 to 15 inches or more) in order to permit the necessary free travel of mechanical elements located within the skirt 13.

The upper face of the top platform is provided with important elements in the novel apparatus combinations in the form of a plurality of locating devices which are preferably rugged, hemispherical bosses of substantial size, for instance about 1 to 8 inches in diameter depending upon the size of the equipment involved.

The plan view of the top platform 23 in FIG. 2 illus trates one embodiment of the locating or positioning hemispherical bosses 26, 27, 28 and 29 which are welded to the upper face of that platform; and the dotted circle 30 represents a suitable location for another such boss which may be employed as an additional locating device or used in lieu of boss 29 or in lieu of boss 28. In addition, the optional backstops at the rear of platform 23 assist in depositing a loaded container onto the platform in suitable registry therewith by preventing the container from being placed too far to the rear of the platform. These backstops may be constructed of short strong lengths of channel or angle iron standing on end with that end of each firmly attached to the platform 23 by welding, etc., and they project one or more v feet above the platform. In the absence of such backstops, the location of a boss at the stop 30 becomes more desirable.

I The container is also provided with a locating element at its bottom in the form of the crossed l beams 33, 34 (see FIG. 1) which are connected together at their central intersection by welding or other appropri ate means. These beams are constructed of steel or other strong materials; accordingly they also serve to support and reinforce the tank 10. Optionally, they may be connected to the rim 35 of tank 10 by means of suitable columns (not shown) or other suitable frame work. Beams 33 and 34 project below the bottom of the tank 10 for a distance that is somewhat greater than the height or radius of the hemispherical bosses 26, etc. for they are adapted to rest in the flat spaces on the face of platform 23 between the pair of bosses 26 and 27 and also the pair 28 and 29 and support the bottom of the container above the bosses when the container 10 has been loaded onto the top platform. When tank 10 is resting on the platform in substantial registry therewith, which need not be exact, the center of the bottom flange of beam 33 lies approximately upon a phantom line 133 (see FIG. 2) and beam 34 lies along the phantom line 134 on platform 23.

The combination of a multiple platform structure movable in two directions with a locating device in the form of locating bosses that are adapted to engage complementary locating elements in the form of the beams 33 and 34 attached to the bottom of the container 10 renders the entire platform structure selfaligning This provides important advantages in respect to depositing a heavy tank or other equipment rapidly and easily. A fork lift truck operator can pick up tank 10 with a fork that is wider than the spread of the pair of bosses 26 and 27, carry it over the center of platform 23 until the opposite side of the tank strikes one or both of the backstops 31 and 32 and then lower the tank onto platform 23 after visually checking that a projecting end of the beam 34 is approximately centered with the pair of bosses 26 and 27. Careful registry is not necessary here for if there is misalignment between the bottom of beam 34 and the flat space along the phantom line 134, the edge of beam 34 will probably descend onto the slope of the boss 26 or 27, and the force exerted by the weight of the container will provide a camming action which will shift the easily movable platform 23 either right or left and thereby permit the beam to settle into the flat space between these bosses. If the beam is so far out of alignment that it descends on the apex of one of the bosses, it is only necessary for the operator to elevate the container with the fork lift and reposition it before lowering it again. Similarly if beam 33, descends upon the sloping sides of bosses 28 and 29, a camming action will move the platform 23 nearer to the front and similar results are obtainable when the pair of central bosses are in the location designated as 28 and 30 or 29 and 30. The latter two arrangements prevent the beam 33 from being too far back on the platform and the backstops 31 and 32 may be omitted, but this may slow down the loading operation to some extent.

Although bosses of hemispherical configuration are greatly preferred, it is also contemplated that other shapes having sides with a suitable slope having an inclination between about and 75 relative to the horizontal (preferably about 45 to 60) can be employed, including cones and pyramids that are desirably truncated, or even pieces of angle iron inverted and having their two parallel edges welded to the platform 23.

It will also be appreciated that the locating elements 33 and 34 may have a configuration other than that of the I-beams shown. For instance, the bottom flange of these beams may be omitted so that they have a T- shaped cross section, in which case the bosses 26 and 27 would be spaced closer together than in FIG. 1. Alternatively, they may be hollow box beams of rectangular cross section. Another possible modification is inverted channel members with the open side facing downward to engage a single row of bosses.

At least one of the complementary locating elements should have sloping surfaces inclined at between about 15 and to the horizontal, and preferably more than 30, in order to provide the necessary camming action for pushing the top platform 23 into approximate registry with tank 10 when the latter is being lowered while off center relative to the platform receiving it. However, it is not necessary that the sloping surface have a constant angle of inclination as is apparent from the hemispherical bosses 26, etc. illustrated. It is also contemplated that the round bosses 26, etc. could be attached to the bottom of tank 10 and crossed I-beams 33 and 34 could be affixed to the upper surface of platform 23, but this modification would be less desirable for a number of reasons. For example, the bosses 26 and 27 would not project from the side of the tank to assist the fork lift truck operator in depositing it on the platform as is the case with the beams 33 and 34. Also, the bottom of tank 10 would have to be strengthened in some manner to permit it to be set down on any flat surface in view of the small area of the bosses; and even then, the bosses are likely to damage the flat surface 7 supporting the tank.

The frame 16 is designed to permit additional equipment or other objects to be lowered into engagement with the container 10. In addition to the base plate 15, the frame 16 is made up of other strong and rigidly connected components at the sides 36 and 37, the top 38 and the cross brace 39. Attached to the top and cross brace of the frame are two hydraulic rams 40 which push the follower plate 12 and the lower end of the assembly of twin pumps 41 by means of the piston rods 42 down into the open upper end of tank 10 and into contact with the fluid or semisolid contents therein. These pumps are hydraulically operated pumps which are fastened to the follower plate 12 and their individual cross bar 43, but their tubes both pass through openings in the cross brace 39 instead of being connected thereto.

The inlets 45 of the pumps are in the follower plate 12. The pumps discharge into flexible rubber hoses (not shown). The follower plate 12 not only carries the twin pumps assembly downward but also exerts a substantial pressure to force air out of the container and keep it out in conjunction with two heavy rubber gaskets (not shown) of about 2-inch diameter and separated by a space of about 3 inches on the edge of the follower.

Precise registration is necessary to avoid damage to the hydraulic rams 40, especially their piston rods 42. Such registration is assured by removably attaching three or more guides 47 equidistantly spaced around the tank rim 35, which guides are inclined at an angle of 60 from the horizontal. The guides may be constructed of 2-inch stainless steel pipe welded to the schematically shown locking pliers 48 of the vise grip type to provide a quick acting clamping means. Despite their simplicity, these guides are extremely effective in 7 accomplishing self-alignment of a precise nature by merely pushing the follower plate 12 down by means of the hydraulic rams 40 as described hereinafter. While the slope of the slanted guides 47 may be somewhat smaller in certain cases, it is usually preferred to have an inclination between about 45 and 60.

The operation of the apparatus of this invention may best be described in connection with the handling of a specific material which provides difficult handling problems because the present invention is particularly suited for overcoming such problems. These materials are silicone sealants and adhesives, and their compounding involves the preparation of alkyl polysiloxanes and admixture with a number of additives including a catalyst and a coloring material in the production of the compositions described, for example, in US. Pat. No. 3,077,465, and elsewhere. These are fluid, gel or semisolid materials with viscosities ranging, e.g., from about 12,000 to 1,000,000 centipoises at 25C. Such polymeric siloxane materials are difficult to handle for two reasons; one is their extreme viscosity which makes them difficult to pump, and the other is the necessity of eliminating ainentrapment at this uncatalyzed state, which would make the end product (sealant) unacceptable to the market.

In describing one procedure utilizing the instant apparatus a 48inch (I.D.) tank bearing a temporary cover (not shown) is delivered by a fork lift truck for handling in the apparatus of this invention while a batch of silicone polymers in the tank is being pumped through hoses for mixing with the catalyst and coloring components. The total weight of the tank and its contents is about 3,000 pounds.

With the beam 34 in estimated alignment with the phantom line 134 on the table 23, the operator drives his lift truck forward with the tank 10 elevated above platform 23 until the back of tank 10 touches the backstops 31 and 32 (FIG. 2); and this is followed by lowering the tank onto the platform after a quick glance has indicated that the near or front end of the I-beam 34 is not far out of alignment with the flat space between the platform bosses 26 and 27. This is a rapid and efficient operation which can be performed by one man, because good alignment of the locating members is not necessary to obtain a good approximate registry of the tank on the platform 23 which has a diameter of about 57 inches or approximately 8 inches more breadth than any element of the platform structure therebelow. For example, with half-round bosses 26 and 27 of 3-inch diameter and spaced at 7 inches between their centers, in one particular embodiment, beams 33 and 34 may be as much as about 3 inches out of exact alignment and still provide a good approximate registry with the platform, for the edge 33 or 34 exerts sufficient camming action bearing against the rounded or sloping surface of bosses 26, etc. as the beam is gently lowered to shift the easily movable top platform 23 enough in any necessary horizontal direction to allow the bottom flange of the beam to come to rest in the space between the bosses.

After removal of the temporary cover from tank 10, four of the upwardly extending slanted guides 47 are rapidly attached to rim 35 and the clamps 48. This quick installation of the guides is a great convenience because those projecting guides would be a distinct nuisance at earlier and later stages, especially when the tank 10 is being deposited and removed within the confines of frame 16, platform 23 and the follower plate 12. Next the hydraulic rams 40 are actuated to lower the gasketed follower plate 12 into the open end of tank 10 to exclude the air from the top of the tank and also to seal the tank by means of the gaskets and to immerse the inlets 45 of the pumps. FIG. 1 illustrates this stage of the procedure in an operation in which the tank 10 and platform 11 are adequately centered relative to one another but out of registry with a follower plate 12 thereabove. However, the equipment has selfaligning capabilities and the left side of follower plate 12 comes into contact with the left guide 47 and as the follower 12 continues downward, it exerts a camming action to push tank 10 on top platform 23 to the left as the roller bearing units 24 and 25 slide to the left along the round rails 20 on intermediate platform 17. After entering tank 10 and coming into contact with the surface of the contents therein, the follower plate 12 is pressed against the surface of the fluids with a pressure of about 10 to 25 lbs. per square inch which is equivalent to a total force of about 15 thousand to 45 thousand pounds on the tank 10 and supporting structure therebeneath. Accordingly the hardened steel rails 14 and 20 have a diameter of 2 inches and the bearing units are appropriately sized to handle such heavy loads.

Such operations are strikingly different from prior art methods which involved a group of men manhandling or wedging a heavy container into position with crowbars and suffering occasional damage to hydraulic rams for insertion of a follower plate or other equipment when it was not in perfect registry with a tank therebelow as a result of an operators error. In contrast, the present apparatus can be operated by a single man a saving in reduction time, labor cost and maintenance expenses as a result of the rapid and automatic aligning characteristics of the present apparatus. It will also be appreciated that this apparatus can be employed with many other types of materials handling procedures, as exemplified by installing lids or covers on large containers, especially where a heavy lid is installed or a heavy pressure is required for the installation.

While the present invention has been described chiefly in connection with a single embodiment and a few modifications, it will be apparent to those skilled in the art that many other modifications, variations and embodiments are within the purview of this invention. Accordingly this invention should not be construed as limited in any particulars except as may be recited in the appended claims or required by the prior art.

I claim:

1. A self-aligning platform structure which comprises a plurality of substantially horizontal parallel base rails afiixed to the upper surface of a base member, an intermediate platform having bearing means therebeneath coacting with said base rails for supporting said intermediate platform for rectilinear movement along said base rails, a plurality of substantially horizontal parallel platform rails affixed to the top of said intermediate platfomi and longitudinally oriented substantially perpendicularly to the length of said base rails, a top platform for supporting a container and having bearing means therebeneath coacting with the platform rails for supporting said top platform for rectilinear movement along said platform rails, whereby said top platform is supported for easy movement in any horizontal direction relative to said base rails, at least one locating device on the upper surface of said top platform for engaging at least one complementary locating element on the bottom surface of a container as said container vertically approaches said platform, at least one of the locating means projecting from the supporting said surface, and at least one of said locating means having a sloping surface capable of exerting any necessary camming action during the engagement of said locating means to provide any necessary horizontal movement of said top platform for locating said container in predetermined registry on said top platform.

2. A structure according to claim 1 including a container supported on said top platform in at least an approximate position for the engagement of additional equipment with said container, guide means rigidly affixed to said container and capable of engaging said equipment during a vertical approach thereof to said container for providing any necessary horizontal movement of said top platform and container for locating said container in precise predetermined registry with said equipment.

3. A structure according to claim 2 in which said guide means extends above said container.

4. A structure according to claim 3 in which said guide means has an inclined surface capable of engaging said additional equipment during the vertical approach thereof, and the angle of inclination with the horizontal of said inclined surface is sufficient to provide any necessary camming action during any said approach engagement for providing any necessary horizontal movement of said container for precise registry.

5. A structure according to claim 2 in which said guide means is removably attached to said container with quick acting clamp means.

6. A structure according to claim 2 in which said additional equipment includes a vertically movable follower plate adapted to enter the top of said container and maintain substantial and sealing contact with the upper surface of the contents of said container, said follower plate is mounted for vertical movement guided by a vertically extending frame and said frame is fixed in position relative to said base rails.

7. A structure according to claim 1 in which at least a portion of the sloping surface of said locating means is inclined at an angle of more than 30 relative to the horizontal.

8. A structure according to claim I in which said locating means includes at least one hemispherical boss.

9. A structure according to claim 1 in which said top platform is provided with a plurality of hemispherical bosses spaced for locating therebetween an elongated locating element projecting from the bottom of said container.

10. A structure according to claim 1 in which said bearing means are recirculating linear roller bearings having spaced rollers.

11. A structure according to claim in which said rails are of circular cross section, and at least one of said bearing means includes two sets of bearings having the roller axes thereof disposed at opposite and sub- 10 stantial inclinations to the horizontal for engaging the sides of a rail to prevent the accidental disengagement of a bearing means from the rail.

12. A combination of a self-aligning platform structure and a container which comprises a plurality of substantially horizontal parallel cylindrical base rails affixed to the upper surface of a base member, an intermediate platform having lower bearing means therebeneath coacting with said base rails for supporting said intermediate platform for rectilinear movement along said base rails, a plurality of substantially horizontal parallel cylindrical platform rails affixed to the top of said intermediate platform and longitudinally oriented substantially prependicularly to the length of said base rails, a top platform for supporting a container and having upper bearing means therebeneath coacting with the platform rails for supporting said top platform for rectilinear movement along said platform rails, said bearing means being recirculating linear roller bearings having spaced rollers, each of said lower and upper bearing means including two sets of bearings having the roller axes thereof disposed at opposite and substantial inclinations to the horizontal for engaging the sides of a rail to prevent the accidental disengagement of a bearing means from the rail, whereby said top platform is supported for easy movement in any horizontal direction relative to said base rails, a plurality of locating bosses projecting above the upper surface of said top platform for locating therebetween a horizontally elongated locating element projecting below the bottom surface of said container as said container vertically approaches said platform, and at least one of said locating means having a sloping surface inclined at an angle of more than 30 relative to the horizontal and capable of exerting any necessary camming action during the engagement of said locating means to provide any necessary horizontal movement of said top platform for locating said container in predetermined registry on said top platform; a loaded container so supported on said top platform in at least an approximate position for engaging a vertically movable follower plate adapted to enter the top of said container and maintain substantial and sealing contact with the upper surface of the contents of said container, said plate being mounted for 7 vertical movement guided by a vertically extending frame and said frame being fixed in position relative to said base rails, and a guide means rigidly and removably attached to said container with quick acting clamp means, said guide means having inclined surfaces extending above said container and capable of engaging said follower plate during the vertical approach thereof, and the angle of inclination with the horizontal of said inclined surfaces being sufficient to provide any necessary camming action during any said approach engagement for providing any necessary horizontal movement of said container for precise predetermined registry with said plate. 

1. A self-aligning platform structure which comprises a plurality of substantially horizontal parallel base rails affixed to the upper surface of a base member, an intermediate platform having bearing means therebeneath coacting with said base rails for supporting said intermediate platform for rectilinear movement along said base rails, a plurality of substantially horizontal parallel platform rails affixed to the top of said intermediate platform and longitudinally oriented substantially perpendicularly to the length of said base rails, a top platform for supporting a container and having bearing means therebeneath coacting with the platform rails for supporting said top platform for rectilinear movement along said platform rails, whereby said top platform is supported for easy movement in any horizontal direction relative to said base rails, at least one locating device on the upper surface of said top platform for engaging at least one complementary locating element on the bottom surface of a container as said container vertically approaches said platform, at least one of the locating means projecting from the supporting said surface, and at least one of said locating means having a sloping surface capable of exerting any necessary camming action during the engagement of said locating means to provide any necessary horizontal movement of said top platform for locating said container in predetermined registry on said top platform.
 2. A structure according to claim 1 including a container supported on said top platform in at least an approximate position for the engagement of additional equipment with said container, guide means rigidly affixed to said container and capable of engaging said equipment during a vertical approach thereof to said container for providing any necessary horizontal movement of said top platform and container for locating said container in precise predetermined registry with said equipment.
 3. A structure according to claim 2 in which said guide means extends above said container.
 4. A structure according to claim 3 in which said guide means has an inclined surface capable of engaging said additional equipment during the vertical approach thereof, and the angle of inclination with the horizontal of said inclined surface is sufficient to provide any necessary camming action during any said approach engagement for providing any necessary horizontal movement of said container for precise registry.
 5. A structure according to claim 2 in which said guide means is removably attached to said container with quick acting clamp means.
 6. A structure according to claim 2 in which said additional equipment includes a vertically movable follower plate adapted to enter the top of said container and maintain substantial and sealing contact with the upper surface of the contents of said container, said follower plate is mounted for vertical movement guided by a vertically extending fraMe and said frame is fixed in position relative to said base rails.
 7. A structure according to claim 1 in which at least a portion of the sloping surface of said locating means is inclined at an angle of more than 30* relative to the horizontal.
 8. A structure according to claim 1 in which said locating means includes at least one hemispherical boss.
 9. A structure according to claim 1 in which said top platform is provided with a plurality of hemispherical bosses spaced for locating therebetween an elongated locating element projecting from the bottom of said container.
 10. A structure according to claim 1 in which said bearing means are recirculating linear roller bearings having spaced rollers.
 11. A structure according to claim 10 in which said rails are of circular cross section, and at least one of said bearing means includes two sets of bearings having the roller axes thereof disposed at opposite and substantial inclinations to the horizontal for engaging the sides of a rail to prevent the accidental disengagement of a bearing means from the rail.
 12. A combination of a self-aligning platform structure and a container which comprises a plurality of substantially horizontal parallel cylindrical base rails affixed to the upper surface of a base member, an intermediate platform having lower bearing means therebeneath coacting with said base rails for supporting said intermediate platform for rectilinear movement along said base rails, a plurality of substantially horizontal parallel cylindrical platform rails affixed to the top of said intermediate platform and longitudinally oriented substantially prependicularly to the length of said base rails, a top platform for supporting a container and having upper bearing means therebeneath coacting with the platform rails for supporting said top platform for rectilinear movement along said platform rails, said bearing means being recirculating linear roller bearings having spaced rollers, each of said lower and upper bearing means including two sets of bearings having the roller axes thereof disposed at opposite and substantial inclinations to the horizontal for engaging the sides of a rail to prevent the accidental disengagement of a bearing means from the rail, whereby said top platform is supported for easy movement in any horizontal direction relative to said base rails, a plurality of locating bosses projecting above the upper surface of said top platform for locating therebetween a horizontally elongated locating element projecting below the bottom surface of said container as said container vertically approaches said platform, and at least one of said locating means having a sloping surface inclined at an angle of more than 30* relative to the horizontal and capable of exerting any necessary camming action during the engagement of said locating means to provide any necessary horizontal movement of said top platform for locating said container in predetermined registry on said top platform; a loaded container so supported on said top platform in at least an approximate position for engaging a vertically movable follower plate adapted to enter the top of said container and maintain substantial and sealing contact with the upper surface of the contents of said container, said plate being mounted for vertical movement guided by a vertically extending frame and said frame being fixed in position relative to said base rails, and a guide means rigidly and removably attached to said container with quick acting clamp means, said guide means having inclined surfaces extending above said container and capable of engaging said follower plate during the vertical approach thereof, and the angle of inclination with the horizontal of said inclined surfaces being sufficient to provide any necessary camming action during any said approach engagement for providing any necessary horizontal movement of said container for precise predetermined registry with said plate. 